1. Field of the Invention
The present invention relates generally to a medical device, and more particularly to a stent.
2. Description of the Related Art
Medical devices commonly known as stents have been used to reinforce and strengthen damaged body passages such as the ureter, the urethra, bile ducts, blood vessels, the trachea, coronary arteries, the gastro intestinal tract, and the esophagus. For example, blood vessels can collapse, dilate, become partially occluded or otherwise damaged by disease or other causes. An aneurysm or stricture in the blood vessel often requires a stent to strengthen the vascular wall in the area of the damage. Stents can also be used to help prevent kinking or occlusion of blood vessels such as veins or arteries and to prevent their collapse after dilatation or other treatment.
Stents can be broadly divided into two main categories: balloon expandable stents and self-expanding stents. For balloon expandable stents, the material of the stent is deformed through the inflation of a balloon, so that after the balloon is deflated the stent remains in the deployed state. Such stents are manufactured in a collapsed or delivery state, ready for delivery, and may be expanded to the deployed state when inside the body passageways.
Self-expanding stents are also delivered in a delivery state and when released from a constraining delivery system the stent expands to its deployed state of a predetermined size. This effect is often achieved by using the elasticity of the material and/or a shape-memory effect.
Traditional stents may have a fixed diameter. Because of this, a hospital may need to maintain an inventory of multiple stents each with a different diameter because each patient may have different sized body passageways. Also, traditional stents are hard to deploy and remove from body passageways as they need to be preset into a delivery state in order to fit within a body passageway. After traditional stents are deployed, they are reset into the delivery state so that they can be removed from the body passageway.
Therefore, a need continues to exist for a stent which may be used in a variety of body passageways, and is easy to deploy, remove and manufacture.